Adaptive neuroplasticity in the default mode network contributing to absence of central sensitization in primary dysmenorrhea

Introduction

Primary dysmenorrhea (PDM), the most prevalent gynecological problem among women of reproductive age, presents as a regular pattern of cyclic menstrual pain. The presence or absence of central sensitization (i.e., pain hypersensitivity) in cases of PDM is a contentious issue. Among Caucasians, the presence of dysmenorrhea is associated with pain hypersensitivity throughout the menstrual cycle, indicating pain amplification mediated by the central nervous system. We previously reported on the absence of central sensitization to thermal pain among Asian PDM females. In this study, functional magnetic resonance imaging was used to reveal mechanisms underlying pain processing with the aim of explaining the absence of central sensitization in this population.

Methods

Brain responses to noxious heat applied to the left inner forearm of 31 Asian PDM females and 32 controls during their menstrual and periovulatory phases were analyzed.

Results and discussion

Among PDM females experiencing acute menstrual pain, we observed a blunted evoked response and de-coupling of the default mode network from the noxious heat stimulus. The fact that a similar response was not observed in the non-painful periovulatory phase indicates an adaptive mechanism aimed at reducing the impact of menstrual pain on the brain with an inhibitory effect on central sensitization. Here we propose that adaptive pain responses in the default mode network may contribute to the absence of central sensitization among Asian PDM females. Variations in clinical manifestations among different PDM populations can be attributed to differences in central pain processing.

MEG-based Classification and Grad-CAM Visualization for Major Depressive and Bipolar Disorders with Semi-CNN

Major depressive disorder (MDD) and bipolar disorder (BD) are two major mood disorders with partly overlapped symptoms but different treatments. However, their misdiagnosis and mistreatment are common based on the DSM-V criteria, lacking objective and quantitative indicators. This study aimed to develop a novel approach that accurately classifies MDD and BD based on their resting-state magnetoencephalography (MEG) signals during euthymic phases. A revisited 3D CNN model, Semi-CNN, that could automatically detect brainwave patterns in spatial, temporal, and frequency domains was implemented to classify wavelet-transformed MEG signals of normal controls and MDD and BD patients. The model achieved a test accuracy of 96.05% and an average of 95.71% accuracy for 5-fold cross-validation. Furthermore, saliency maps of the model were estimated using Grad-CAM++ to visualize the proposed classification model and highlight disease-specific brain regions and frequencies. Clinical Relevance - Our model provides a stable pipeline that accurately classifies MDD, BD, and healthy individuals based on resting-state MEG signals during the euthymic phases, opening the potential for quantitative and accurate brain-based diagnosis for the highly misdiagnosed MDD/BD patients.

A novel beamformer-based imaging of phase-amplitude coupling (BIPAC) unveiling the inter-regional connectivity of emotional prosody processing in women with primary dysmenorrhea

Objective. Neural communication or the interactions of brain regions play a key role in the formation of functional neural networks. A type of neural communication can be measured in the form of phase-amplitude coupling (PAC), which is the coupling between the phase of low-frequency oscillations and the amplitude of high-frequency oscillations. This paper presents a beamformer-based imaging method, beamformer-based imaging of PAC (BIPAC), to quantify the strength of PAC between a seed region and other brain regions.Approach. A dipole is used to model the ensemble of neural activity within a group of nearby neurons and represents a mixture of multiple source components of cortical activity. From ensemble activity at each brain location, the source component with the strongest coupling to the seed activity is extracted, while unrelated components are suppressed to enhance the sensitivity of coupled-source estimation.Main results. In evaluations using simulation data sets, BIPAC proved advantageous with regard to estimation accuracy in source localization, orientation, and coupling strength. BIPAC was also applied to the analysis of magnetoencephalographic signals recorded from women with primary dysmenorrhea in an implicit emotional prosody experiment. In response to negative emotional prosody, auditory areas revealed strong PAC with the ventral auditory stream and occipitoparietal areas in the theta-gamma and alpha-gamma bands, which may respectively indicate the recruitment of auditory sensory memory and attention reorientation. Moreover, patients with more severe pain experience appeared to have stronger coupling between auditory areas and temporoparietal regions.Significance. Our findings indicate that the implicit processing of emotional prosody is altered by menstrual pain experience. The proposed BIPAC is feasible and applicable to imaging inter-regional connectivity based on cross-frequency coupling estimates. The experimental results also demonstrate that BIPAC is capable of revealing autonomous brain processing and neurodynamics, which are more subtle than active and attended task-driven processing.

Brain Dynamics Altered by Photic Stimulation in Patients with Alzheimer's Disease and Mild Cognitive Impairment

Individuals with mild cognitive impairment (MCI) are at high risk of developing Alzheimer's disease (AD). Repetitive photic stimulation (PS) is commonly used in routine electroencephalogram (EEG) examinations for rapid assessment of perceptual functioning. This study aimed to evaluate neural oscillatory responses and nonlinear brain dynamics under the effects of PS in patients with mild AD, moderate AD, severe AD, and MCI, as well as healthy elderly controls (HC). EEG power ratios during PS were estimated as an index of oscillatory responses. Multiscale sample entropy (MSE) was estimated as an index of brain dynamics before, during, and after PS. During PS, EEG harmonic responses were lower and MSE values were higher in the AD subgroups than in HC and MCI groups. PS-induced changes in EEG complexity were less pronounced in the AD subgroups than in HC and MCI groups. Brain dynamics revealed a "transitional change" between MCI and Mild AD. Our findings suggest a deficiency in brain adaptability in AD patients, which hinders their ability to adapt to repetitive perceptual stimulation. This study highlights the importance of combining spectral and nonlinear dynamical analysis when seeking to unravel perceptual functioning and brain adaptability in the various stages of neurodegenerative diseases.

Interactions of BDNF Val66Met Polymorphism and Menstrual Pain on Brain Complexity

The irregularity and uncertainty of neurophysiologic signals across different time scales can be regarded as neural complexity, which is related to the adaptability of the nervous system and the information processing between neurons. We recently reported general loss of brain complexity, as measured by multiscale sample entropy (MSE), at pain-related regions in females with primary dysmenorrhea (PDM). However, it is unclear whether this loss of brain complexity is associated with inter-subject genetic variations. Brain-derived neurotrophic factor (BDNF) is a widely expressed neurotrophin in the brain and is crucial to neural plasticity. The BDNF Val66Met single-nucleotide polymorphism (SNP) is associated with mood, stress, and pain conditions. Therefore, we aimed to examine the interactions of BDNF Val66Met polymorphism and long-term menstrual pain experience on brain complexity. We genotyped BDNF Val66Met SNP in 80 PDM females (20 Val/Val, 31 Val/Met, 29 Met/Met) and 76 healthy female controls (25 Val/Val, 36 Val/Met, 15 Met/Met). MSE analysis was applied to neural source activity estimated from resting-state magnetoencephalography (MEG) signals during pain-free state. We found that brain complexity alterations were associated with the interactions of BDNF Val66Met polymorphism and menstrual pain experience. In healthy female controls, Met carriers (Val/Met and Met/Met) demonstrated lower brain complexity than Val/Val homozygotes in extensive brain regions, suggesting a possible protective role of Val/Val homozygosity in brain complexity. However, after experiencing long-term menstrual pain, the complexity differences between different genotypes in healthy controls were greatly diminished in PDM females, especially in the limbic system, including the hippocampus and amygdala. Our results suggest that pain experience preponderantly affects the effect of BDNF Val66Met polymorphism on brain complexity. The results of the present study also highlight the potential utilization of resting-state brain complexity for the development of new therapeutic strategies in patients with chronic pain.

The socio-economic impact of multidrug-resistant nosocomial infections: a qualitative study

The burden of healthcare-associated infections (HCAIs) has traditionally been measured using clinical and economic outcomes. We conducted semi-structured interviews with 18 patients or their caregivers affected by HCAI caused by multidrug-resistant organisms to better understand the human impact of HCAI. Most patients had misconceptions about HCAI and antimicrobial resistance, leading to strong negative feelings towards HCAIs despite positive views of their healthcare providers. Communication issues across power imbalances need to be addressed to help deal with trauma of HCAIs. A holistic approach to HCAIs incorporating patient perspectives will likely help guide policymakers developing solutions to improve patient outcomes.

Unaltered intrinsic functional brain architecture in young women with primary dysmenorrhea

Primary dysmenorrhea (PDM), painful menstruation without organic causes, is the most prevalent gynecological problem in women of reproductive age. Dysmenorrhea later in life often co-occurs with many chronic functional pain disorders, and chronic functional pain disorders exhibit altered large-scale connectedness between distributed brain regions. It is unknown whether the young PDM females exhibit alterations in the global and local connectivity properties of brain functional networks. Fifty-seven otherwise healthy young PDM females and 62 age- and education-matched control females participated in the present resting-state functional magnetic resonance imaging study. We used graph theoretical network analysis to investigate the global and regional network metrics and modular structure of the resting-state brain functional networks in young PDM females. The functional network was constructed by the interregional functional connectivity among parcellated brain regions. The global and regional network metrics and modular structure of the resting-state brain functional networks were not altered in young PDM females at our detection threshold (medium to large effect size differences [Cohen's d ≥ 0.52]). It is plausible that the absence of significant changes in the intrinsic functional brain architecture allows young PDM females to maintain normal psychosocial outcomes during the pain-free follicular phase.

Encoding of menstrual pain experience with theta oscillations in women with primary dysmenorrhea

Theta oscillation (4–7 Hz) is well documented for its association with neural processes of memory. Pronounced increase of theta activity is commonly observed in patients with chronic neurogenic pain. However, its association with encoding of pain experience in patients with chronic pain is still unclear. The goal of the present study is to investigate the theta encoding of sensory and emotional information of long-term menstrual pain in women with primary dysmenorrhea (PDM). Forty-six young women with PDM and 46 age-matched control subjects underwent resting-state magnetoencephalography study during menstrual and periovulatory phases. Our results revealed increased theta activity in brain regions of pain processing in women with PDM, including the right parahippocampal gyrus, right posterior insula, and left anterior/middle cingulate gyrus during the menstrual phase and the left anterior insula and the left middle/inferior temporal gyrus during the periovulatory phase. The correlations between theta activity and the psychological measures pertaining to pain experience (depression, state anxiety, and pain rating index) implicate the role of theta oscillations in emotional and sensory processing of pain. The present study provides evidence for the role of theta oscillations in encoding the immediate and sustained effects of pain experience in young women with PDM.

Retrospective review of prognostic factors, including 1p19q deletion, in low-grade oligodendrogliomas and a review of recent published works

The purpose of the present study was to investigate potential prognostic factors in low-grade oligodendrogliomas (LGOs), particularly 1p19q deletion, due to its proven prognostic significance in anaplastic oligodendrogliomas. We carried out a retrospective review of patients with a histological diagnosis of LGO between 1990 and 2000 in Auckland and Wellington, New Zealand. All cases underwent central histopathological review and FISH testing for 1p19q status. Univariate analysis of potential prognostic factors including 1p19q status, age, tumour size, tumour crossing midline, tumour enhancement, extent of surgery and seizures at diagnosis was carried out. Thirty-one patients were eligible and FISH testing was successful in 28 specimens (90%). Twenty-three specimens (82%) had 1p19q deletion; four (14%) had no 1p19q deletion; and one (4%) had 1p deletion alone. At a median follow-up of 87 months (0-147 months), median survival had not been reached and no significant difference in overall survival (OS) based on 1p19q status was detected (1p19q deletion OS 56%; 1p19q intact OS 0%; 1p deletion alone 100% (P = 0.38)). None of the other prognostic factors investigated reached statistical significance. We confirmed the high incidence (82%) of combined 1p19q deletion in LGOs and the feasibility of successful FISH testing in paraffin embedded specimens up to 10-years-old. Analysis of potential prognostic factors was limited by the lack of events during the follow-up period.

Epithelioid trophoblastic tumor: a case report

Epithelioid trophoblastic tumor is a rare and distinctive pathologic entity within the complex family of gestational trophoblastic disease. We describe a case of epithelioid trophoblastic tumor occurring in a 34-year-old woman, who presented with a large uterine tumor 3 years following an uncomplicated pregnancy. The clinicopathologic findings in this case are typical of this unusual entity and consistent with current literature, with the exception of negative beta-human chorionic gonadotrophin levels. The distinguishing features from other intermediate trophoblastic tumors and tumor-like lesions are discussed.

Epithelioid trophoblastic tumor: a case report

Epithelioid trophoblastic tumor is a rare and distinctive pathologic entity within the complex family of gestational trophoblastic disease. We describe a case of epithelioid trophoblastic tumor occurring in a 34-year-old woman, who presented with a large uterine tumor 3 years following an uncomplicated pregnancy. The clinicopathologic findings in this case are typical of this unusual entity and consistent with current literature, with the exception of negative beta-human chorionic gonadotrophin levels. The distinguishing features from other intermediate trophoblastic tumors and tumor-like lesions are discussed.

Approach to risk reduction in manufacturing firms in Australia

A survey of the 100 largest manufacturing firms in Australia has revealed that there is a lack of emphasis on controlling the incidence of high severity injuries and diseases. In a considerable number of organizations, there appears to be a reliance on the attitude of employees and safety training to control risk. There seems to be a lack of knowledge among the respondents of information sources which can be used to assess both risk and proposed control measures. The results suggest that Robens type legislation may be of limited utility in controlling risk in the workplace and a more definitive approach to identifying hazards and instituting appropriate control measures should be provided to organizations.

Absence and labour turnover in a foundry attributable to respiratory disease

A survey of foundry workers was undertaken to assess the effect of respiratory disease on both absence in the year prior to the survey and labour turnover since a cross-sectional study of respiratory morbidity five years previously. The presence of a wheeze, but not an objective disturbance of airway function, was predictive of absence. Those with respiratory illness, detected in the survey five years previously, were no more likely to have left the foundry than those without such illness. Limited job opportunities may discourage moulders with respiratory disease from leaving the foundry. Absence was not related to cigarette smoking, the presence of bronchial hyperreactivity, or a positive skin test to common allergens. In view of the small number of subjects in this study, studies of larger work populations should be undertaken to further assess the effect of subjective and objective indices of respiratory morbidity on absence and labour turnover.

Respiratory disease in foundry workers

A survey was carried out in a steel foundry in Brisbane to evaluate the nature and frequency of respiratory symptoms and to assess ventilatory function. The foundry used many moulding processes including the Furane, Isocure, Shell, carbon dioxide, and oil sand systems. Nasal symptoms and wheeze were often reported, particularly by workers in the general foundry and core shop, and on a semiautomated line. By contrast, workers in the aftercast section not exposed to fumes or vapours from the various moulding processes reported these symptoms less often. Of 46 workers exposed to moulding fumes and vapours, 11 had developed a wheeze while working at the foundry. Wheeze and other respiratory tract symptoms were often attributed by the workers to exposure to substances at work, particularly from the Shell process which uses phenol formaldehyde resin and hexamethylenetetramine. Symptoms were reported also, but less often, on exposure to materials used in the Furane process (urea formaldehyde and furfuryl alcohol) and the Isocure process (methylene diphenyl diisocyanate, phenol formaldehyde, and dimethylethylamine). Ventilatory function studied over Monday and Friday showed a small and inconsistent changes. The six subjects working on the semiautomated line showed a small decrease in FEV1 (+/- SEM) (208 +/- 70 ml) only on Monday; this differed significantly from that in 17 aftercast workers (9 +/- 50 ml, p less than 0.05). Ventilatory function recorded before work on Monday morning showed no evidence of chronic airway obstruction in any group. Most environmental measurements were below the threshold limit values (TLV) except in the general foundry, where furfuryl alcohol was detected at concentrations of up to 50 ppm and formaldehyde at 4 ppm. The onset of symptoms in relation to exposure to various fumes and vapours suggests that both irritant and hypersensitivity mechanisms are present. As environmental modifications had occurred recently the apparent hypersensitivity may relate to past exposure levels above the TLV.